Data Backup Glossary (Letter S)

SaaS: Software as a Service
Software as a Service (SaaS) is a software delivery method that provides access to software and its functions remotely as a web-based service. Software as a Service allows organizations to access business functionality at a cost typically less than paying for licensed applications since SaaS pricing is based on a monthly fee. Also, because the software is hosted remotely, users don’t need to invest in additional hardware. Software as a Service removes the need for organizations to handle the installation, setup, and often daily upkeep and maintenance. Software as a Service may also be referred to as simply hosted applications.

SaaS: Storage as a Service
Storage as a Service (SaaS) is a storage model in which a business or organization (the client) rents or leases storage space from a third-party provider. Data is transferred from the client to the service provider via the Internet and the client then accesses the stored data using software provided by the storage provider. The software is used to perform common tasks related to storage, such as data backups and data transfers. Storage as a Service is popular with SMBs because there usually are no start-up costs (for example, servers, hard disks, IT staff, and so on) involved. Businesses pay for the service based only on the amount of storage space used. Storage as a Service may also be called hosted storage.

A Storage Area Network (SAN) is a high-speed subnetwork of shared storage devices. A storage device is a machine that contains nothing but a disk or disks for storing data. A SAN’s architecture works in a way that makes all storage devices available to all servers on a LAN or WAN. As more storage devices are added to a SAN, they too will be accessible from any server in the larger network. In this case, the server merely acts as a pathway between the end user and the stored data. Because stored data does not reside directly on any of a network’s servers, server power is utilized for business applications, and network capacity is released to the end user.

SAN fabric
The hardware that connects workstations and servers to storage devices in a SAN. The SAN fabric enables any-server-to-any-storage device connectivity through the use of Fibre Channel switching technology.

SAN services
A technology used by businesses to obtain greater flexibility in their data storage. A Storage Area Network (SAN) provides raw storage devices across a network, and is typically sold as a service to customers who also purchase other services. SAN services may also be administered over an existing, local fiber network, and administered through a service subscription plan.

Scratch disk
Space dedicated on a hard drive for temporary storage of data. Scratch disks are commonly used in graphic design programs, such as Adobe Photoshop. Scratch disk space is only for temporary storage and cannot be used for permanently backing up files. Scratch disks can be set to erase all data at regular intervals so that the disk space is left free for future use. The management of scratch disk space is typically dynamic, occurring when needed.

The first full backup of company data.

Secret storage technology
A technology for encrypting and hiding data on a hard drive, flash drive, or when transferring files. Secret storage is a portion of encrypted data, hidden in some file or FAT/FAT32/NTFS partitions. To the end-user, it looks like a folder in which he may add files and folders and protect it with a password.

Selective backup
A type of backup where only the user-specified files and directories are backed up. A selective backup is commonly used for backing up files which change frequently or in situations where the space available to store backups is limited. Also called a partial backup.

Serial storage architecture
Serial storage architecture (SSA) is an open industry-standard interface that provides a high-performance, serial interconnect technology used to connect disk devices and host adapters. SSA serializes the SCSI data set and uses loop architecture that requires only two wires: transmit and receive. The SSA interface also supports full-duplex, so it can transmit and receive data simultaneously at full speed.

Server cage area
The area where a company stores its data center equipment. This area is protected from personnel access.

Service-level agreement
A service-level agreement (SLA) is an agreement between a service provider, such as an IT department, an Internet services provider, or an intelligent device acting as a server, and a service consumer. A service level agreement defines parameters for measuring the service, and states quantitative values for those parameters.

Slack space
The unused space in a disk cluster. The DOS and Windows file systems use fixed-size clusters. Even if the actual data being stored requires less storage than the cluster size, an entire cluster is reserved for the file. The unused space is called the slack space. DOS and older Windows systems use a 16-bit file allocation table (FAT), which results in very large cluster sizes for large partitions. For example, if the partition size is 2 GB, each cluster will be 32 K. Even if a file requires only 4 K, the entire 32 K will be allocated, resulting in 28 K of slack space. Windows 95 OSR 2 and Windows 98 resolve this problem by using a 32-bit FAT (FAT32) that supports cluster sizes smaller than 1K.

Small and medium enterprise (SME)
Companies whose headcount or turnover fall below certain limits. In the United states, a small business is often defined as having fewer than 100 employees. A medium-size business is often defined as having fewer than 500 employees.

Small to mid-size business (SMB)
Companies whose headcount or turnover fall below certain limits. In the United states, a small business is often defined as having fewer than 100 employees. A mid-size business is often defined as having fewer than 500 employees.

Snapshot backup
A virtual copy of a device or file system. Snapshots imitate the way a file or device looked at the precise time the snapshot was taken. It is not a copy of the data, only a picture in time of how the data was organized. Snapshots can be taken according to a scheduled time and provide a consistent view of a file system or device for a backup and recovery program to work from.

Solid state disk
A solid state disk (SSD) is a high-performance plug-and-play storage device that contains no moving parts. SSD components include either DRAM or EEPROM memory boards, a memory bus board, a CPU, and a battery card. Because SSDs contain their own CPUs to manage data storage, they are a lot faster (18MBps for SCSI-II and 35 MBps for UltraWide SCSI interfaces) than conventional rotating hard disks; therefore, they produce highest possible I/O rates.

Spin valve
Another name for a giant magnetoresistive(GMR) head. The term was coined by IBM.


  • The capacity of a device to hold and retain data.
  • Short for mass storage.

Storage bay bridge
Storage bridge bay (SBB) is a specification that defines mechanical, electrical, and low-level enclosure management requirements for an enclosure controller slot that will support a variety of storage controllers from a variety of independent hardware vendors and system vendors. Any storage controller design based on the SBB specification will be able to fit, connect, and operate within any storage enclosure controller slot design based on the same specification.

Storage Consolidation
The concept of centralized storage where resources are shared among multiple applications and users. Traditionally, organizations have deployed servers with direct-attached storage (DAS) as file servers. However, many organizations are facilitating server consolidation by deploying network-attached storage (NAS). NAS provides a single purpose device that can provide CIFS and NF- connected storage that can scale from gigabyte to petabytes.

Storage device
A device capable of storing data. The term usually refers to mass storage devices, such as disk and tape drives.

Storage footprint
The amount of energy, physical space, and other equipment necessary to run a data storage management system.

Storage management
The tools, processes, and policies used to manage storage networks and storage services such as virtualization, replication, mirroring, security, compression, traffic analysis, and other services. The phrase also encompasses other storage technologies, such as process automation, storage management and real-time infrastructure products, and storage provisioning. In some cases, the phrase storage management may be used in direct reference to storage resource management (SRM).

Storage management initiative specification
Storage management initiative specification (SMI-S) is an interface standard that enables interoperability in both hardware and software between storage products from different vendors used in a SAN environment. The interface provides common protocols and data models that storage product vendors can use to ensure end user manageability of the SAN environment.

Based on the CIM and Web-Based Enterprise Management (WBEM) standards, SMI-S adds common interoperable and extensible management transport, automated discovery, and resource locking functions. SMI-S was developed by the Storage Networking Industry Association (SNIA) in 2002.

Storage networking
A high-speed network of shared storage devices. The storage network is used by IT departments to connect different types of storage devices with data servers for a larger network of users. As more storage devices are added to the storage network, they too will be accessible from any server in the larger network.  Storage networking is a phrase most commonly associated with enterprises and data centers.

Storage optimization
The implementation and management of tiered storage solutions to obtain a lower cost per capacity across a corporation or enterprise. Storage optimization is an information lifecycle management (ILM) strategy.

Storage over IP
Storage over IP (SoIP) technology refers to the merging of Fibre Channel technologies with IP-based technology to allow for accessing storage devices over TCP/IP networks. SoIP is the framework for storage area networking (SAN) using Internet Protocol (IP) networks to directly connect servers and storage. SoIP products are designed to support transparent interoperability of storage devices based on Fibre Channel, SCSI, and a new class of Gigabit Ethernet storage devices using iSCSI and iFCP. Existing Fibre Channel or SCSI devices, such as servers with host bus adapters (HBAs) or storage subsystems, can be included in an SoIP storage network without modification.

Storage resource management
Storage resource management (SRM) refers to software that manages storage from a capacity, utilization, policy, and event management perspective. SRM includes bill-back, monitoring, reporting, and analytic capabilities that allow you to drill down for performance and availability.
Key elements of SRM include asset management, charge back, capacity management, configuration management, data and media migration, event management, performance and availability management, policy management, quota management, and media management.

Storage service provider
A storage service provider (SSP) is a company that provides computer storage space and related management services. SSPs also offer periodic backup, archiving, and the ability to consolidate data from multiple company locations so that data can be effectively shared.

Storage virtualization
Storage virtualization is the amalgamation of multiple network storage devices into what appears to be a single storage unit. Storage virtualization is often used in a SAN (storage area network), a high-speed subnetwork of shared storage devices, and makes tasks such as archiving, backup, and recovery easier and faster. Storage virtualization is usually implemented via software applications.

To copy data from a CPU to memory, or from memory to a mass storage device.

The process of distributing data across several storage devices to improve performance.

In magnetic disk drive storage technology, the fluctuation of magnetization due to thermal agitation. When the areal density—the number of bits that can be stored on a square inch of disk media—of a disk medium reaches 150 gigabits per square inch, the magnetic energy holding the bits in place on the medium becomes equal to the ambient thermal energy within the disk drive itself. When this happens, the bits are no longer held in a reliable state and can “flip,” scrambling the data that was previously recorded. Because of superparamagnetism, hard drive technologies are expected to stop growing once they reach a density of 150 gigabits per square inch.

In Fibre Channel, a receiver’s identification of a transmission word boundary.

Synthetic backup
A synthetic backup is identical to a regular full backup in terms of data, but it is created when data is collected from a previous, older full backup and assembled with subsequent incremental backups. The incremental backup will consist only of changed information. A synthetic backup is used when time or system requirements do not allow for a full complete backup. The end result of combining a recent full backup archive with incremental backup data is two kinds of files which are merged by a backup application to create the synthetic backup. Benefits to using a synthetic backup include a smaller amount of time needed to perform a backup, and lower system restore times and costs. This backup procedure is called “synthetic” because it is not a backup created from original data.